Screen for paper-pulp.



II. F. STORRER.

SCREEN FOR PAPIERI PULP. APPLICATION FILED MAR. 2, 1915.

Patented Dec. 14, 1915.

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H. F. STORRER.

l SCREEN FOR PAPER PULP.

APPLICATION 4FILED MAR. 2, 1915, 1 14 Patented Deo. 14, 1915 a, 9 2 SHEETS-SHEETZ.

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Specication-of Letters Patent. Patented Mpeg., 1d., 119115.

Application le'd March 2, 1915. Serial No. 11,525. i

To all whom z't may concern:

lBe it known that l, HERMANN F. STORRER, a citizen of the Republic of Switzerland, and residing in the` city, county, and State of New York, have invented certain new and Improved Screens for Paper-Pulp, of which* the following is a specification.

My invention relates to screens for paper pulp and particularly to an agitator of improved construction adapted not only to prevent clogging 'of thel screenbut also to aid the screening action and thus to increase th'e capacity of the apparatus and the quality of the product.

An illustrative embodiment of vmy invention is shown in the accompanying drawings a in 'which- Figure 1 is a plan of a rotary screen showi ing my improved agitator associated therewith; Fig. 2 is a longitudinal section therethrough; Fig. 3 is an end elevation of the same; Fig. t is a transverse section of the same; and Fig. 5 is a diagram illustrating the movement of the agitator.

The common practice in the paper making industry is to comminute the material from which the paper is to be made e. g. wood of suitable tiber,-and pass the same in liquid suspension, through a screen of suitably fine mesh or grid, to eliminate coarse fibers, lumps, knots, etc., which` would be unsuitable foruse in the grade of paper which is to be made. One of the difficulties inl this process is to prevent the clogging of the screen apertures since the capacity of the apparatus is at once lowered when this takes place.

Furthermore, the pulp stock contains brous as well as filler elements, and it is highly desirable that these constituents *of the paperpass through the screen in normal, uniform quantity so that they are mingled in proper proportion in the screened suspension, since the quality and even texture of the paper is aHected thereby. rllhe pulp stock to be screened must therefore be kept agitated so that these elements are uniformly mingled f therein.

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rotating cylindrical screen l2 isv'supported within the vat by hollow hubs 13 lclosed at their outer ends by the stationary heads 14, through ports 15 in which the scrpened pulp suspension y flowing into the screen from the vat passes lout to the paper making machinery.v Gear rings 16 on these hubs mesh with pinions 17 on the shaft 18, driven through gear 19, the latter rigid with the worm gear 2l engaged by the worm 22 on the shaft vof the pulley 23 which in turn is driven by belt 24.- from pulley 25 on the first motion shaft 26 carrying fast and loose pulleys 27, 28. A spray pipe 29 passes longitudinally through the screen above the level of the suspension therein and directs jets of water, under heavy pressure, upward through the screen apertures, thus washing into the olf-take pipe 30 any coarse material which may have adhered to the outer surface of the screen.

rllhe agitator, with which the present invention is especially concerned, is suspended in the vat below the lower portion of the rou tary screen. In the form here shownthe screen comprises a reticulated plate 31 eX- tending the length of the screen and having a curvature substantially corresponding to that of the screen. llt is suspended by pairs of arms 32 and 33 carried up over the opposite sides of the vat and terminating on the one side in bearing rings 34 surrounding adjustable eccentrics 35 mounted'on shaft 26, and on the other side in a joint rigid with the upper ends of a pair of vertically ar- `ranged leaf springsy 36. The latter are bolted at 37 to bosses 38 cast on the side of the vat. Adjusting screws 39 which bear against" straps 40 on the springs, may be provided to afford means for varying the action of the springs, for' example, by shortening the working length thereof, or by imparting an initial tension thereto. l Tie rods Vil extend- 'ing between sockets 42 on the arms of each pair of suspension arms `32, 33 further strengthen and add rigidity like structure. I

lWhen the shaft 26 is driven, the cams 35 impart an oscillating motion to the agitator which is diagrammatically shown in Fig. 5. Near the eccentric all the points move invan approximate circle. The farther from the eccentric and toward the spring support, the less becomes the vertical oscillation. 'The to the cradlemotionis illustrated byv ellipses, the vertical short diameter of `which grows lem and lessl -insures the uniform distribution of the fiber and filament elements throughout the stock,- a feature of importance as above pointed out.

The oscillatory movement of the agitator plate, first toward and then away from the cylinder screen, creates alternate pressure and suction efforts with relation to the latter which are of great importance. Thus the pressure effort, on the approach of the screen to thecylinder causes the suspension liquid and fine pulp elements to pass with abnormal rapidity through the screen apertures, thus accelerating the action of the screen and increasing the capacity of the apparatus. The suction effort on the other hand, serves to draw off the screen surface the coarse particles retained thereby and thus clears the screen apertures and keeps the latter at its maximum capacity for the work demanded of it.

The action of the agitator is rendered particularly effective by making the plate of such size that it extends from end to end of the cylinder screen, while its upper edges lie only so far below the surface of the pulp stock in the vat as may be necessary to avoid splashing.

The extent of movement of the agitator y canbe regulatedby adjusting the eccentric to give a greater or less throw. The speed of rotation of the eccentric which will give the best result, varies with the pulp stock in the vat. It should be such however, that the pressure and suction eorts are well dened, if the best results are to be secured.

The spring is preferably so arranged that it tends constantly to press the vibrator in one direction and the cam has to overcome its effort in one direction only. A silent operation of the device without unnecessary wear upon the parts is secured by this arrangement.

' Various modifications of construction will readily suggest-themselves by which the same result may be accomplished but which do not depart from what I claim as my invention.

I claim as my invention l. In a pulp screening apparatus, a vat for pulp stock, a rotary screen within the vat, an agitator dipping into the stock beneath the screen and extending upward on opposite sides thereof, and a spring support for one side of said agitator.

2. In a pulp screening apparatus, avat for pulp stock, a rotary screen within the vat, an agitator dipping into the stock beneath the screen and extending upward on opposite sides thereof, a Vibratory' device operatively connected to one side of said agitator and a spring support for the opposite side of said agitator.

3. In a pulp screening apparatus, a vat for the pulp stock, a. rotary screen within the vat, an agitator dipping into the stock beneath the screen and curvedto curvature of the screen, supports for said agitator extending outside the vat on opposite sides of the screen, cam means operatively connected to the support on one side of the screen for moving the agitator in one direction and spring means operatively connected to the support on the opposite side for moving said agitator in the other direction.

4. In a pulp screening apparatus, a vat for the pulp stock, a rotary screen within the vat, an agitator dipping into the stock and extending outside the vat on opposite sides of the screen, and a spring support for one end of said agitator.

5. In a pulp screening apparatus, avat for the pulp stock, a rotary screen within the vat, an agitator dipping into the stock and extending outside the vat on opposite sides of the screen, and -a tensioned spring support for one end of said agitator.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing Witnesses.

HERMANN F. STORRER.

Witnesses:

ALBRECHT GRoss, OTTO F. GOEPPINGER. 

